In a letter to President Bush today, European Union leaders write that progress on the Kyoto treaty on climate change is crucial to strong U.S.-European relations and that the president must find the “political courage” to move forward with treaty negotiations. The letter, signed by Swedish Prime Minister Goran Persson, whose country holds the E.U. presidency, and European Commission President Romano Prodi, asks Bush to agree to a high-level dialogue on Kyoto with the E.U. before the next round of international climate talks scheduled for July. The E.U. has grown increasingly concerned that Bush will try to kill the Kyoto deal. Last week, Bush broke a campaign promise and said he would not seek to limit power plants’ emissions of carbon dioxide, the main greenhouse gas.